动态代理（JDK、CGLIB）

提供代理接口

public interface Rent {
	public void massage();

}

被代理类

public class Host implements Rent{

	@Override
	public void massage() {
		System.out.println("房东要租房！");
	}
}

代理类

public class ProxyCompant implements InvocationHandler{
	//获取被代理的对象
	private Object target;
	public void setTarget(Rent target){
		this.target = target;
		
	}
	
	//产生代理对象
	public Object getProxy(){
		return Proxy.newProxyInstance(this.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
		
	}
	//调用被代理对象的方法
	@Override
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		
		Object result = method.invoke(target, args);
		return result;
	}

}

使用代理对象

public class Client {
	public static void main(String[] args) {
		//传入真实对象
		Host host = new Host();
		//创建代理对象
		ProxyCompant pt = new ProxyCompant();
		//设置被代理对象
		pt.setTarget(host);
		//产生代理对象
		Rent proxy = (Rent)pt.getProxy();
		//调用被代理对象的方法
		proxy.massage();		
	}
}

被代理类

public class PersonService {
    public PersonService() {
        System.out.println("PersonService构造");
    }
    public void setPerson() {
        System.out.println("PersonService:setPerson");
    }
}

代理类

public class CglibProxyIntercepter implements MethodInterceptor {
    @Override
    public Object intercept(Object sub, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("执行前...");
        Object object = methodProxy.invokeSuper(sub, objects);
        System.out.println("执行后...");
        return object;
    }
}

调用代理对象

public class Test {
    public static void main(String[] args) {       
        //代理类class文件存入本地磁盘
        System.setProperty(DebuggingClassWriter.DEBUG_LOCATION_PROPERTY, "D:\code");
        Enhancer enhancer = new Enhancer();
        //设置代理对象
        enhancer.setSuperclass(PersonService.class);
        //设置回调方法
        enhancer.setCallback(new CglibProxyIntercepter());
        //生成代理对象
        PersonService proxy= (PersonService)enhancer.create();      
        //执行被代理对象的方法  
        proxy.setPerson();           
     } 
}